Antibackfire device for internal combustion engines



25, 4- 1.. c. MAH ER 2,340,071

ANTIBACKFIRE DEVICE FOR INTERNAL COMBUS TION ENGINES Filed April 25.1940

INVENTOR,

Patented Jan. 25, 1944 OFFICE,

ANTIBACKFIRE DEVICE FOR INTERNAL COMBUSTION ENGINES Laurence C. Maher, Asbury Park, N. J. Application April 25, 1940, Serial No. 331,577 24 Claims. c1, 48-192) This invention relates to back-fire preventers, mixers and vaporizers for fuel mixtures and more particularly to anti-back-fire devices for internal combustion engines. The device also serves as a homogenizer for the fuel mixture, and may serve as a vaporizer; and though it is noted that in most of the claims the invention is not limited to Vaporizers and in some claims the invention is not limited to back-fire preventers and in others it is not limited to mixers, and in some is not limited to engines.

One object of the invention is to provide an improved anti-back-fire device which is free of moving parts in which the fuel is divided, redivided and again divided, while being passed in contact with heat absorbing metal, thus to cool any back-fire flame below the ignition point, thereby to quench the flame.

Other objects of the invention are to provide an improved device of this kind in which the fuel as it comes from the carbureter is one or more times divided, partly recombined, redivided and'again divided and again recombined before it passes to the engine thereby to thoroughly mix and homogenize the fuel.

Other objects are to warm the fuel when in this divided state, thus to thoroughly vaporize it.

Additional objects of the invention are to effect simplicity and efficiency in such devices and to provide an extremely simple device of this kind which is efficient, economical, durable, and very reliable in operation, and economical to manufacture and install.

Still other objects of the invention will appear as the description proceeds; and While herein details of the invention are described in the specification and some of the claims, the invention as described in the broader claims is not limited to these, and many and various changes may be made without departing from the scope of the invention as claimed in the broader claims.

The inventive features for the accomplishment of these and other objects are shown herein in connection with a back-fire preventer and homogenizer interposed in the intake conduit of an internal combustion engine between the carbureter and engine, and which briefly stated comprises a housing having opposite walls and one or more bafiie plates therebetween dividing the housing into chambers communicating with'adjacent sections of the conduit. If there are two bafile plates, they form an intermediate chamber between the other two chambers. As shown, the bafile plate or plates may each have a central imperforate impact baflie portion alined with the conduit, and openings around said portions rj'e ceiving chill-tubes passed through the openings, each chill-tube having an axial bore havingan open end portion in one chamber and a head forming a closed end portion in an adjacent chamber, the head having radial perforations entering the bore. A tubular wire mesh fits in said bore covering the perforations and projects from said open end. H

A cap fits over the closed end of the tube and has an end recess larger in diameter than the bore and receiving said projecting end with the end edge of the mesh againstthe-end wall of the cap, said cap having a plurality of radial apertures communicating with said recess.

Normally fuel mixture passes from the carbureter intoone chamber, thence through the perforations mesh and bore to another chamber (and similarly to a third chamber, if present) and finally to the engine cylinders, thus thor oughly homogenizing the mixture. During back fire, combustion gases pass in the opposite direction, but are cooled as they pass 7 I, perforations, bore and mesh, thus quenchin gall flame.

This invention relates generally tofanti-flare{ back devices for fuel devices for internal com bustion engines, and has for its main object the provision of means wherein the natural running action of the fuel of such engines, through the carbureter, causes the fuel to be homogenized, to provide a homogenous gas fuel for such engines, and also to provide means whereby in the case of a misfire of any cylinder of a multiple cylinder engine, the device will prevent back-fire and the consequent discharge from the carbureter of a flaming gasoline stream. The present device is intended to be located between the usual carbureter and the intake manifold of the engine, but may be used for other purposes.

An advantage of the present construction is that it provides means for creating a gasoline fuel charge, whereby all of the cylinders in a multiple engine will receive afull fuel charge but without starvationfof the endcylinders ofa',

group of a multiple cylinder engine.

The main advantage in the present construc tion, however, is theprovision of means, as

previously stated, to prevent the flame of back fire from reaching and setting fire to the normal gasoline charge in the carbureter itself.

' The present device, while not so limited, is especially adapted for use in aeroplane engines,

and therefore provides for greater safety in the operation of aeroplanes, and is also specifically through the.

. of the invention,

Fig. 1 is a fragmental side elevation showin the improved back-fire preventer used to prevent back-fire in a multi-cylinder internal combustion engine; a

Fig. 2 is a plan of the housing with the top wall removed, showing the baflie plate and heads of the chill tubes;

Fig. 3 is an axial vertical sectional view, partly in elevation, showing the interior of one form of back-fire preventer having two chambers in the housing Fig. 4 is a fragmental axial vertical sectional view, partly in elevation, showing the interior of a back-fire preventer, having two baflle plates dividing the housing into three chambers;

Fig. 5 is a side elevation showing one of the chill-tubes;

Figs. 6 and 7 are side and end elevations of the cap for the chill-tube.

The improved back-fire preventer I is here shown in combination with a multi-cylinder internal combustion engine having an intake manifold |2 and a carbureter l3. The back-fire preventer I0 is interposed between the manifold and the conduit M to the carbureter and comprises a housing l5, l6, 11 comprising an axially vertically disposed axially short cylindrical side wall I (Fig. 3) having an inner rabbet |8 at each edge. A circular top wall l6 and a circular bottom wall H are seated in said rabbets l8 respectively, and are respectively provided with large bosses 20, 2| surrounding central openings 22, 23 axially alined with the conduit l4, registering with the openings of said conduit and manifold. The bottom boss 2| is provided with inwardly countersunk screw receiving openings 25 adapted to receive screws adapted to be screwed into the boss 23 (Fig. 1)' around the opening into manifold for securing the bottom Wall to the manifold. The boss 20 is provided with threaded bolt holes adapted to receive screw bolts 28 (Fig. 1) by which the top wall I6 is secured to the flange 29 of the connduit l4. Bolts 30 pass through said walls l5, l1 and a bafile plate 32 and clamp the walls in said rabbets I8.

The transverse baffie plate 32 is disposed across the housing and is integral with or engaged with the side wall |5 slightly nearer to the upper wall l6 than to the lower wall, dividing the housing into a small intake chamber 33 at the carbureter side, and a large discharge chamber 34 at the manifold side, the bailie being provided with a central imperforate impact bairle portion 35 and an inner series and an outer series of circumferentially arranged circular chill-tube-receiving openings 36, 31.

Chill-tubes 39, of copper or other suitable heat absorbing metal are disposed in said open.- ings 36, 31. Each tube has a disk shaped head 39 in said smaller chamber 33 and an elongated cylindrical body portion 40 passed through said circular openings 36, 31 respectively into the larger chamber 34, each tube having an axial bore 4| extending entirely through the body portion into, but not entirely through the head 39, the head having radial perforations 42 extending into the bore.

A tubular or scroll-shaped mesh 45 of fine heat absorbing wire of Monel metal or other suitable metal is fitted in said bore 4| from end to end thereof and projects from the free end of the bore and covers the inner end of the perforations 42. A cap 41 about the same diameter as said head is carried on each body portion 40 against the bafile plate 32 and has a large bore 48 as long as the body portion 40 for snugly receiving the body portion, said large bore having a reduced end or recess 49 at the end wall 50 of the cap and receiving the projecting end of the wire mesh 45, with the end edge 5| of the mesh engaged against said end wall 50 of the cap. Said cap hasa plurality of radial apertures 62 establishing communication between said recess and the larger chamber.

The back-fire preventer, in normal operation acts as a homogenizer serving to thoroughly mix and homogenize the elements of the fuel mixture. When the mixture is drawn from the carbureter, it strikes and is jarred against said impact portion 35 in the smaller chamber 33 and then diverted in all radial directions to the chill tubes and finely divided as it passes through the apertures 42 and adjacent mesh, portions of the mixture being recombined and mixed as they pass through the passage bore 4! and recess 49, to be again divided as the fuel passes from the recess through the mesh into the apertures 62, thence to the larger chamber, there to be again combined as it passes to the opening 23 and intake manifold to the engine cylinders. The apertures 42 and 62 are made large enough not to throttle the fuel mixture; and it is found that the device used as a homogenizer is very efficient, and especially so at high speeds, and provides a full rich fuel charge to all cylinders of a multicylinder engine without starvation or giving a lean mixture to the end cylinders.

During back-fire the preventer serves the function of cooling any of the burning mixture that may pass back from the intake manifold, thereby thoroughly eliminating combustion and quenching flame by cooling the burning gases by contact with the cold walls of the apertures 42, 62, the passage bore 4| and the cold wires of the mesh adjacent to the bar and apertures.

The apertures 42 and 62 are made small enough to give the above explained cooling function, but large enough not to throttle or wiredraw the fuel mixture.

The main advantage of the back-fire preventer is its surprising efiiciency as a back-fire preventer, as shown by the olhcial test that it has received.

In testing this device all known methods of backfiring were tried under the most severe conditions. The test procedure was as follows:

1. The engine was run on a very lean mixture produced by a special adjustable jet on the carburetor. The mixture was leaned gradually until the engine no longer ran under its own power buthad to be motored by the dynamometer. This resulted in occasional violent backfires, with intermittent popping back.

2. One intake valve was adjusted to remain slightly open at all times, simulating the condition of a broken valve spring. The first test was repeated under this condition, with severe backfiring at all engine speeds and mixtures.

3. Four intake valves were caused to remain open varying amounts. Under this condition backfiring was so violent that the engine would not run under its own power at all but had to be motored by the dynamometer. This test was run continuously for one'hour with violent rapid-fire backfiring so intense that the manifold and back fire preventer became too hot to touch although the engine water temperature was only 70 F. The ignition timing was also changed over a wide range.

The results of the test showed the device en.- tirely satisfactory since under the most severe backfiring condition no flame was observed at the carbureter. Observations were made from one side of the carbureter, against a dark black background, and also from a platform above, looking down into the carbureter.

From the above test it is noted that device was eflicient as a back-fire preventer even when too hot to touch with the hand In view of this fact the device may be jacketed and heated with the exhaust gases, the water from the engine water jacket, or other suitable medium, as in my above mentioned patent, thereby to convert the cold mixture coming from the carbureter into heated vapor thus to further increase the efficiency of the fuel, thus giving a triple function to the backfire preventer.

The form of back-fire preventer of Fig. 4, is similar in principle to that of Figs. 1 to 3 except that the gases have to pass in series through two sets of chill tubes before passing the preventer from the manifold to the carbureter and vice versa, thus more certainly eliminating all chance of back-fire passing to the carbureter and more thoroughly homogenizing the mixture in normal operation.

In this form of the invention a pair of spaced baflie plates 32a, 32b are disposed across the housing against theshoulders I a, I512 on the side wall l5, and cooperating with the side wall and top and bottom walls to provide two outer chambers 33a, 34a and an intermediate chamber 33b, the chambers 33a, 34a communicating with the conduit I 4 and intake manifold respectively. Each bafiie plate 32a, 32b has a plurality of circular openings 36, 37 therein the opening of one plate being offset from openings of the other plate; to provide spaces for the chill-tubes passed through said circular openings respectively, each tube having a head 39 in one of the chambers 33a or 331) and a cap 41 in the chamber 331). The head and cap are provided with radial perforations :42, 62 respectively. a tubular wire mesh fitting in the bore as in Figs. Sand 6.

The back-fire preventer of Figs. 1 to 3 is designed to eliminate back-fire under any condition that ever takes place in practice. The-pr venter of Fig. 4.is-designed to eliminate back fire under still more adverse circumstances. In the device of Fig. 4, the'fiame of back-fire has to pass first through bores; apertures and mesh when passing from chamber 34a to 3-31); and if by any possible chance thefiame should pass into chamber 33?), it would surely be extinguished when the gases pass through another set of bores, apertures and mesh in passing from chamber 33b to chamber 33a.

As a homogenizer, the form of Fig. 4 is also very eflicient, as the mixture after it strikest-he impact portion 35 and is divided as it passes through the bores, apertures and mesh of the chill tubes carried by plate 32a, is again combined and mixed in the intermediate chamber 331) after which it passes through the bores, apertures and mesh of chill-tubes carried by bafiie plate 32b, and .is again combined in chamber 34a before it passes to the manifold and cylinders. i

From the foregoing it will be obvious that a new method has been developed for the prevention of back-firing in caloric engines, which includes the use of a device between the intake manifold and the carbureter, to prevent the explosive force of a misfire, or discharge from 'a misfired pressure from a group piston which may create back-flaming discharge of gasoline from the carburetor in the prevention of fire hazard, in the vehicle to which this device is attached. The invention claimed is:

1. A back-fire preventer comprising a housing having a baille plate therein dividing the housing into chambers having inlet and outlet openings respectively, said baffle plate having openings.

therein; tubular devices in the openings, each device having an axial bore and means for closing both ends of the bore; each device having sets of radial perforations extending from end portions of said bore into communication with the respective chambers; and a tubular Wire mesh fitting in said-bore and extending from end to end thereof and disposed between the perforations and the axial part of the bore.

2. In a back-fire preventer, the combination of a baflle plate having openings therein; chill-tubes in the openings having means for closing both ends of the tube; said tube having perforations extending from end portions of the tube; and a mesh in said tube between the perforations and the axial part of the tube.

3. In a, back-fire preventer, the combination of a housing divided into chambers; chill-tubes, each having perforations extending from the interior of the tube to the respective chambers; heat absorbing mesh in the tube adjacent to the perforations; said housing being adapted to be warmed enough to assist in vaporizing the fuel while the tubes and to prevent back-fire.

4. A device comprisin means providing a passage; partition means across the passage having openings therein; tubes in openings, each having an axial bore; means for closing both ends of said tubes and having sets of radial perforations extending from said bore into communication with the respective chambers; and a. tubular wire mesh fitting in said bore and extending from end to end thereof and between the perforations and the axial part of the bore.

5. In a back-fire preventer a housing having opposite walls and a baflle plate therebetween dividing the housing into chambers each wall having an opening; the baffle having a central imperforate impact bafile portion alined with one of the openings, and openings around said portions; chill-tubes passed through said last named openings, each having an axial bore having an open end portion in one chamber and a closed end portion in the other having radial perforations near the closed end; a tubular mesh of metallic wire fitting in said bore and projecting from said openend and covering the perf0ra tions; and a cap fitted over the open end of the tube and having an end recess larger in diameter than the bore and receiving said projecting end with'the end edge of the mesh against the end wall of the cap; said cap having a plurality of radial apertures communicating with said recess;

perforations are cool enough said back-fire preventer serving, during back-fire; the function of cooling the burning mixture and thoroughly eliminating combustion and quenching flame by contact with the cold walls of the bores and apertures and the cold wires of the mesh.

6. In combination a housing comprising a short cylindrical side wall and top and bottom walls having openings; a baflle plate across the housing dividing the housing into an intake chamber and a discharge chamber; the bafile having a central imperforate impact baille portion alined with the openings, the plate having chill-tubereoeiving openings arranged around said portions; chill-tubes passed through said second openings respectively, each tube having an axial bore having a closed end in one chamber and an open end in the other chamber; said closed end having radial perforations extending into the bore; a tubular wire mesh fitting in said bore from end to end thereof and projecting from said open end and covering the perforations; and a cap over the open end of the tub and against the baffle plate and having a large bore fitting on the open end of the tube and having an end recess larger in diameter than said bore and receiving the wire mesh, with the end edge of the mesh engaged against the end wall of the cap; said cap havin a plurality of radial apertures communicating with said recess.

'7. In combination a housing having an axially vertically disposed axially short cylindrical side wall having an inner rabbet at each edge; a circular top wall and a circular bottom wall seated in said rabbets respectively, each provided with a large central opening provided with a boss; the bottom boss being provided with inwardly countersunk screw receiving openings; the top boss being provided with threaded bolt holes; a baffie plate across the housing and provided with a central imperforate portion surrounded by circular openings; bolts passing through said walls and baflle plate and clamping the walls in said rabbets; and chill tubes in the openings.

8. In combination a, housing having opposite walls each having a central opening and a baffie plate therebetween dividing the housing into chambers; the baiile having a central imperforate impact bafile portion alined with the openings, and openings around said portions; tubes passed through said last named openings, each having closed end portions in the respective chambers provided with perforations near each closed end; a tubular wire mesh fitting in said bore and projecting from said open end and covering the perforations; the device in normal operation, serving to thoroughly mix and homogenize the elements of fuel mixture as it strikes against said impact portion in one chamber and then diverted in all radial directions to the tubes and finely divided as it passes through the apertures and adjacent mesh, portions being recombined and mixed as they pass through the passage bore and recess to be again divided as the fuel passes from the recess through the mesh into the other chamber there to be again combined.

9. In combination a housing having a cylin drical side wall and top and bottom walls; a transverse baflle plate disposed across the housing and integral with or engaging the side wall slightly nearer to the lower side than to the upper and dividing the housing into a small intake chamber and a discharge chamber; the baffle being provided with a central irnperforate impact baffle portion and an inner series and an outer series of circumferentially arranged circular chill-tube-receiving openings; chilltubes passed through said openings, each having an axial bore having closed end portions in the respective chambers having radial perforations therein; and a tubular wire mesh fitting in said bore and covering the perforations.

10. A back-fire preventer comprising a housing comprising a short cylindrical side wall, and top and bottom walls each having an opening therein; a baffle plate across the housing cooperating with the top. and bottom walls to provide upper and lower chambers and having circular openings therein; chill-tubes of copper or other suitable heat absorbing metal, each having a disk shaped head in said upper chamber and an elongated cylindrical body portion passed through said circular openings respectively into the lower chamber, each tube having an axial bore extending entirely through the body portion into, but not through the head, the head having radial perforations extending into the bore; a tubular or scroll shaped heat absorbing fine wire mesh of IMonel metal or other suitable metal fitting in said bore from end to end thereof and projecting from the freexend of the bore and covering the inner end of the perforations; and a cap about the same diameter as said head on each body portion against the baffle plate and having a large bore as long as the body portion receiving the body portion, and having a reduced end or recess at the end wall of the cap and receiving the projecting end of the wire mesh, with the end edge of the mesh engaged against said end wall of the cap; said cap having a plurality of radial apertures establishing communication between said recess and the larger chamber.

11. A back-fire preventer comprising a housing having inlet and outlet openings and comprising a pair of spaced bafile plates across the housing providing two outer chambers and an intermediate chamber; each baffle plate having a plurality of circular openings therein; chill-tubes passed through said circular openings respectively, each tube having an axial bore having closed ends in adjacent'chambers; said closed ends having radial perforations extending from the bore to the chambers adjacent thereto; and a wire mesh in said bore adjacent to the perforations.

12. A back-fire preventer comprising a housing having inlet and outlet openings and comprising top and bottom walls each having an opening therein, and side walls; a pair of spaced baffle plates across the housing cooperating with the top and bottom walls to provide two outer chambers and an intermediate chamber; each bafile plate having a plurality of circular openings therein; chill-tubes passed through said circular openings respectively, each tube having an axial bore having closed end portions in adjacent chambers; said closed end portions having radial perforations extending from the bore to the chambers adjacent thereto; and a tubular wire mesh fitting in said bore and extending from end to end thereof and between the perforations and the axial part of the bore.

13. In combination, a housing; a baflie plate across the housing having openings therein; tubes in the openings having means for closing both ends of the tubes; said tube having perforations extending from end portions of the tube into the respective chambers.

14. A combination as in claim 13,-said perforations being radial.

15. In combination, a metallic housing divided into chambers having inlet and outlet openings respectively; metallic tubes each having closed ends and end groups of fine perforations only extending from the interior of the tube to the respective chambers to establish paths through the perforations and tubes from one chamber to the other; and a heat absorbing mesh in each tube disposed across said paths between the groups.

16. In combination, a housing divided into chambers; chill-tubes each having a large number of radial perforations extending from the interior of the tube to the respective chambers to establish paths through the perforations and tubes from one chamber to the other; and a heatabsorbing mesh in each tube and disposed across said paths between the perforations at one chamber and the perforations at the other chamber.

17. In combination, a pair of chambers; heatconducting tubes each having closed ends extending into the interior of the respective chambers, each end portion of each tube having perforations extending from the interior of the tube to the adjacent chambers; and heat absorbing mesh in the tube adjacent to the perforations.

18. In combination, a housing divided into chambers; chill-tubes each having perforations extending from the interior of the tube to the respective chambers; and heat absorbing mesh in the tube adjacent to the perforations.

19. In combination, a pair of chambers having a heat conducting wall, a wall of each chamber having a large opening therein; tubes each having an end extending into the respective chambers; each end portion of each tube having perforations extending from the interior of the tube to the respective chambers.

20. In combination, a pair of chambers having heat conducting walls; tubes each having closed ends extending into the respective chambers, each end portion of each tube having lateral perforations extending from the interior of the tube to the respective chambers. 21. In combination, a pair of chambers having heat conducting walls; heat conducting tubes, each having its ends in the respective chambers and provided with a large number of substantially equally spaced radial perforations extending from the interior of the tube to the adjacent chamber; said walls being adapted to be warmed enough to assist in vaporizing the fuel.

22. In combination, a pair of chambers each provided with an opening; a plurality of tubes of heat absorbing metal, each tube having its ends in the respective chambers; each tube having an axial bore extending entirely through the body portion into, but not through the end of the tube, each tube having lateral perforations extending from the end of bore into communication with the adjacent chamber.

23. In combination, a pair of chambers near each other; each chamber being respectively provided with a passage opening in the outer wall most remote from the other chamber; a plurality of tubes of heat absorbing metal disposed around and remote from the axes of said openings, leaving an impact face opposite one of the openings; each tube having its ends in the respective chambers substantially against said outer walls of the chambers; each tube having an axial bore extending entirely through the body portion except the ends, each end portion of each tube having fine perforations extending from the bore into communication with the adjacent chamber; the combination serving to thoroughly mix and homogenize the elements of a fuel mixture drawn in at the opening opposite said face, as it strikes and is jolted against said impact face and is then diverted in radial directions to the tubes and finely divided as it passes through the apertures, the divided portions of the fuel bein recombined and mixed as they pass through the passage bore and again divided as the fuel passes through the perforations into the other chamber there to be again combined as it passes to the other opening.

24. In combination, a cylindrical intake chamber; a cylindrical discharge chamber coaxial with and near the intake chamber; the chambers being respectively provided with a large central intake and discharge openings in the outer wall remote from the other chamber the intake chamber being provided with a flat blank impact face opposite the large opening a plurality of tubes of heat absorbing metal disposed axially parallel and remote from said impact face and extending into the respective chambers; each tube having end heads in the respective chambers substantially against the outer walls of th chambers; each tube having an axial bore extending entirely through the body portion into, but not through the head of the tube, each head having radial perforations extending from the bore into communication with the adjacent chamber.

LAURENCE C. MAI-ER. 

